Effect of nitrogen sources and surfactants on cellulase production by fungal strains under submerged cultivation

Cellulase, as a complex enzyme containing endoglucanase, exoglucanase and beta‐glucosidase, acts to hydrolyze cellulose in order to be converted into glucose units. These subunits of cellulase synergistically hydrolyze the cellulosic substrate of industrial importance. The biosynthesis of celluase by microorganisms has been recently paid much attention Nitrogen is one of the important elements required for growth of microorganisms. Provision of utilizable form of nitrogen source to organisms is the basic requirement to be fulfilled for optimal growth. The use of surfactants in the production of hydrolytic enzymes is well known. Many reports have shown the stimulatory effects of surfactants on enzyme production by microorganisms in submerged or solid state fermentation. The effects of several surfactants on the activity of cellulase enzyme were also studied in this study. Among the nitrogen sources, proteose peptone and yeast extract were found quite effective nitrogen sources whereas tween -80 and oil of olive performed well as surfactants by fungal growth and production system.

Increasing the Production of Xenocoumacin 1 by Optimizing the Fermentation Process of Xenorhabdus Nematophila

Background: Xenocoumacin 1 (Xcn 1), a kind of water-soluble antibiotic discovered from the cell-free broth of Xenorhabdus nematophila YL001, has exhibited excellent activity against bacteria, oomycetes and fungi. However, the low yield limits the development and utilization of Xcn1. In order to increase the yield of Xcn1, the fermentation process was optimized in this study. Results: Maltose and proteose peptone were identified as the best carbon and nitrogen sources that significantly affected Xcn1 production using a-factor-at-a-time approach. Response surface methodology was applied to optimize the medium constituents for Xcn1 production by X. nematophila YL001. Higher Xcn1-content (113.65 μg/mL) was obtained after optimizing medium components. The optimal levels of medium components were (g/L): proteose peptone 20.83, maltose 12.74, K2HPO4 3.77. Fermentation conditions, such as initial pH, inoculum size, temperature, rotation speed, liquid volume and the length of fermentation, were also investigated by using a-factor-at-a-time method to get a higher production of Xcn1. X. nematophila YL001 was able to produce higher Xcn1 (153.56 μg/mL) at 25°C, initial pH 7.0, inoculum size 10%, culture medium 75 mL in a 250 mL shake flash with an agitation rate of 150 rpm for 48h. Additionally, kinds, concentrations and adding time of the precursor were also investigated. X. nematophila YL001 was able to produce the highest Xcn1 (173.99 μg/mL) when the arginine was added to the broth with 3 mmol/L at the 12th hour. An overall 243.38% increase in Xcn1 content was obtained as compared with mean observed response at TSB medium.Conclusions: To the best of our knowledge, there are no reports on optimization of fermentation process for Xcn1 production quantified by HPLC. The results show that nutrition, precursors and fermentation conditions had a highly influence on the production of Xcn1 by X. nematophila YL001. The optimized medium and fermentation conditions resulted in a 243.38% increase in Xcn1 production. This work will be helpful for the development of X. nematophila YL001 cultivation process for efficient Xcn1 production and lay a foundation for its industrial production.

Structural and Mechanismic Studies of Lactophoricin Analog, Novel Antibacterial Peptide

Naturally derived antibacterial peptides exhibit excellent pharmacological action without the risk of resistance, suggesting a potential role as biologicals. Lactophoricin-I (LPcin-I), found in the proteose peptone component-3 (PP3; lactophorin) of bovine milk, is known to exhibit antibiotic activity against Gram-positive and Gram-negative bacteria. Accordingly, we derived a new antibacterial peptide and investigated its structure–function relationship. This study was initiated by designing antibacterial peptide analogs with better antibacterial activity, less cytotoxicity, and shorter amino acid sequences based on LPcin-I. The structural properties of antibacterial peptide analogs were investigated via spectroscopic analysis, and the antibacterial activity was confirmed by measurement of the minimal inhibitory concentration (MIC). The structure and mechanism of the antibacterial peptide analog in the cell membrane were also studied via solution-state nuclear magnetic resonance (NMR) and solid-state NMR spectroscopy. Through 15N one-dimensional and two-dimensional NMR experiments and 31P NMR experiments, we suggest the 3D morphology and antibacterial mechanism in the phospholipid bilayer of the LPcin analog. This study is expected to establish a system for the development of novel antibacterial peptides and to establish a theoretical basis for research into antibiotic substitutes.

Bioactive fractions from Streptococcus macedonicus MBF 10-2 produced in an optimized plant-based peptone medium fermentation

Background: Postbiotic fractions of several lactic acid bacteria have potential as microbial therapeutics for skin health and may also appeal to consumers who wish to avoid animal-based products. We aim to establish the optimum plant-peptone fermentation of Streptococcus macedonicus MBF10-2, which possess Bacteriocin Like-Inhibitory Substance activity in our previous study, to produce bacterial bioactive fractions. We evaluate their potential antibacterial and antioxidant actions, and as well assess the preliminary safety for human skin application. Methods: Fermentation was carried out by using plant peptone modified MRS, i.e., soy peptone and Vegitone, a non-animal-carbon sources that substitute proteose peptone in MRS medium. Fractions of MBF10-2 lysate and cell-free supernatant were collected and processed as follows, i.e. cell disruption, fraction separation and fractions freeze-drying. Fractions were confirm for antibacterial properties by the agar well diffusion method and assess for antioxidant activity using DPPH, while safety assessment was carried-out by skin patch assay. Result: Maximum growth of MBF10-2 achieved by fermentation in soy peptone- and in Vegitone-modified media was 9.00 and 7.99 g total cell mass, respectively. The antibacterial property of fractions was most effective against Micrococcus luteus T18. The lysate fraction exhibited a mild antioxidant potency (IC50 840 µg/mL), and all bioactive fractions were proven safe and non-allergenic for human skins. Conclusion: Strep. macedonicus MBF10-2 postbiotics bioactive fractions were indicated as being safe for topical application. This is the first report on the production of a safe Strep. macedonicus bioactive postbiotic possessing mild antibacterial and mild-to-weak antioxidant. Keywords: antibacterial; antioxidant; lysate; soy peptone; Streptococcus macedonicus MBF 10-2

Towards a Better Understanding of the Removal of Carbamazepine by Ankistrodesmus braunii: Investigation of Some Key Parameters

Nowadays, water pollution by pharmaceuticals is a major issue that needs an urgent solution, as these compounds, even when found at trace or ultra-trace levels, could have harmful effects on organisms. Carbamazepine (CBZ) is a pharmaceutical product that is detected as a micropollutant in many water resources. Different treatment methods were lately employed for the removal of CBZ, which are often cheap but inefficient or efficient but expensive. Yet, there are limited available studies on the elimination of this molecule by algae despite their well-known highly adaptive abilities. In this study, the biological treatment of CBZ was carried out using the green microalgae, Ankistrodesmus braunii (A. braunii), which has been reported to be particularly resistant to CBZ toxicity in the literature. The respective effects of the culture medium, the initial inoculum, and CBZ concentrations were studied on CBZ removal. Lastly, the mechanism of CBZ elimination by A. braunii was investigated. The presented data clearly demonstrates that the presence of this molecule did not completely repress A. braunii growth or the ability of these algae to remove CBZ; after 60 days of incubation, the highest percentage of CBZ elimination achieved was 87.6%. Elimination was more successful in Bold’s basal medium than in proteose peptone medium. Finally, the removal mechanism was also investigated to provide a better understanding of the transformation mechanism of this molecule. It was shown that the main removal mechanism was the bioaccumulation of CBZ by A. braunii cells, but the biotransformation of the initial CBZ into metabolites was also observed.

Biosurfactant production by a Bacillus megaterium strain

The aim of the present study was to investigate the ability of Bacillus megaterium IBBPo17 (GenBank KX499518) cells to produce biosurfactant when the growth was done in the presence of long-chain n-alkane n-hexadecane on medium supplemented with yeast extract, proteose peptone, starch, or cellulose. B. megaterium IBBPo17 revealed a higher growth in the presence of n-hexadecane when the medium was supplemented with yeast extract, proteose peptone, or starch, compared with cellulose. Biosurfactant production was higher when B. megaterium IBBPo17 was grown in the presence of n-hexadecane on yeast extract, proteose peptone, or starch supplemented medium, compared with biosurfactant produced on cellulose supplemented medium. A direct correlation between cell growth and biosurfactant production was observed. When the growth of B. megaterium IBBPo17 cells was higher, the decrease in pH values of the medium was higher too, and more amount of CO2 was released. Changes in cell morphology, aggregation of the cells in clusters, and biofilm formation were observed when B. megaterium IBBPo17 was grown in the presence of n-hexadecane on medium supplemented with yeast extract, proteose peptone, starch, or cellulose. Due to its physiological abilities, this Gram-positive bacterium could be a promising candidate for the bioremediation of petroleum hydrocarbon polluted environments.

Comparative Transcriptomics Reveals Distinct Gene Expressions of a Model Ciliated Protozoan Feeding on Bacteria-Free Medium, Digestible, and Digestion-Resistant Bacteria

Bacterivory is an important ecological function of protists in natural ecosystems. However, there are diverse bacterial species resistant to protistan digestion, which reduces the carbon flow to higher trophic levels. So far, a molecular biological view of metabolic processes in heterotrophic protists during predation of bacterial preys of different digestibility is still lacking. In this study, we investigated the growth performance a ciliated protozoan Tetrahymena thermophila cultivated in a bacteria-free Super Proteose Peptone (SPP) medium (control), and in the media mixed with either a digestion-resistant bacterial species (DRB) or a digestible strain of E. coli (ECO). We found the protist population grew fastest in the SPP and slowest in the DRB treatment. Fluorescence in situ hybridization confirmed that there were indeed non-digested, viable bacteria in the ciliate cells fed with DRB, but none in other treatments. Comparative analysis of RNA-seq data showed that, relative to the control, 637 and 511 genes in T. thermophila were significantly and differentially expressed in the DRB and ECO treatments, respectively. The protistan expression of lysosomal proteases (especially papain-like cysteine proteinases), GH18 chitinases, and an isocitrate lyase were upregulated in both bacterial treatments. The genes encoding protease, glycosidase and involving glycolysis, TCA and glyoxylate cycles of carbon metabolic processes were higher expressed in the DRB treatment when compared with the ECO. Nevertheless, the genes for glutathione metabolism were more upregulated in the control than those in both bacterial treatments, regardless of the digestibility of the bacteria. The results of this study indicate that not only bacterial food but also digestibility of bacterial taxa modulate multiple metabolic processes in heterotrophic protists, which contribute to a better understanding of protistan bacterivory and bacteria-protists interactions on a molecular basis.

Influence of the dose of human umbilical cord mesenchymal stem cells on acute inflammation on the peritonitis model in mice

Aim. Study the effect of the dose of human umbilical cord MSCs on acute inflammation on the peritonitis model in mice with intraperitoneal induction of a 3% solution of proteose peptone. Human umbilical cord MSCs can be used in the cell therapy as allogeneic since their properties provide a minimal risk of an immune response with the transplantation MSCs into body. The inflammation follows all diseases and it is base target for MSCs. Methods. The study is used methods of cell biology. Results. Research has shown that 4 hours after the injection of MSCs, the number of macrophages in the peritoneal cavity of mice immediately decreased. The introduction of 5x103 cells per mouse resulted in 78% decrease the number of macrophages in the exudate. Complete return to a normal has been observed with the injection 70–100 x 103 of cells per mouse. In parallel with the decrease in the number of macrophages, their phagocytic activity has decreased, and these changes also depend on the dose of transplanted MSCs. Conclusions. A dose-dependent decrease of acute inflammation of the abdominal cavity in mice was shown with the introduction of MSCs from the human umbilical cord. The number of macrophages into peritoneal exudate has decreased by 78% in 4 hours after the injection 5x103 cells per mouse. Complete suppression of inflammation has observed with the introduction of 70–100 x 103 cells. Inhibition of inflammation is accompanied by a decrease in the phagocytic activity of macrophages, which indicates a change in their polarization. Keywords: human umbilical cord MSCs, inflammation, macrophages, phagocytic activity.

Effect of peptones on the ability of plant pathogenic bacteria to grow on media supplemented with copper sulphate

The extensive use of copper compounds for control of bacterial plant pathogens could lead to selecting strains of the pathogens that are copper-resistant. The ability to grow on a medium supplemented with copper, and therefore the concentration of copper to which bacterial strains are resistant, depends on the composition of the medium used for the test. The effects of different peptones (casitone and proteose peptone No. 3) and different media on the ability of strains of Pseudomonas syringae to grow in presence of copper were determined. Similar results were obtained when casitone was substituted with proteose peptone No. 3 in casitone yeast extract medium, but not when those two peptones were interchanged in King’s B medium. In water, casitone allowed strains of P. syringae pv. actinidiae (Psa) to grow in the presence of higher amounts of copper than proteose peptone No. 3 did. In all cases, resistance to copper was increased with increased peptone concentration.